Numerical Analysis and Mechanical Properties of Nomex™ Honeycomb Core

2017 ◽  
Author(s):  
Yue Liu ◽  
Weicheng Gao ◽  
Wei Liu ◽  
Zhou Hua
Keyword(s):  
Compressive Strength ◽  
Cell Walls ◽  
Mechanical Response ◽  
Compressive Loading ◽  
Fe Model ◽  
Honeycomb Core ◽  
Practical Applications ◽  
Honeycomb Sandwich ◽  
Nomex Honeycomb ◽  
Strength And Stiffness

This paper presents an investigation on the mechanical response of the Nomex honeycomb core subjected to flatwise compressive loading. Thin plate elastic in-plane compressive buckling theory is used to analyze the Nomex honeycomb core cell wall. A mesoscopic finite element (FE) model of honeycomb sandwich structure with the Nomex honeycomb cell walls is established by employing ABAQUS/Explicit shell elements. The compressive strength and compressive stiffness of Nomex honeycomb core with different heights and thickness of cell walls, i.e. double cell walls and single cell walls, are analyzed numerically using the FE model. Flatwise compressive tests are also carried out on bare honeycomb cores to validate the numerical method. The results suggest that the compressive strength and compression stiffness are related to the geometric dimensions of the honeycomb core. The Nomex honeycomb core with a height of 6 mm has a higher strength than that of 8 mm. In addition, the honeycomb core with lower height possesses stronger anti-instability ability, including the compressive strength and stiffness. The proposed mesoscopic model can effectively simulate the crushing process of Nomex honeycomb core and accurately predict the strength and stiffness of honeycomb sandwich panels. Our work is instructive to the practical applications in engineering.

scholarly journals Study on Improving the Fixation Rate of Impregnated Poplar Wood with Maltodextrin and 1,3-Dimethylol-4,5-Dihydroxyethyleneurea

2019 ◽  
Vol 9 (16) ◽  
pp. 3237
Author(s):  
Mingzhen Cai ◽  
Zongying Fu ◽  
Yingchun Cai ◽  
Yue Zhang
Keyword(s):  
Compressive Strength ◽  
Cell Wall ◽  
Fourier Transform ◽  
Cell Walls ◽  
Poplar Wood ◽  
Fixation Rate ◽  
Practical Applications ◽  
Wall Materials ◽  
Impregnated Wood ◽  
Cell Wall Materials

The impregnation of poplar wood (Populus adenopoda Maxim) with 1,3-dimethylol-4,5-dihydroxyethyleneurea and maltodextrin and the effects of ZnCl2 and curing at 103 °C and 120 °C on the fixation rate and the leaching resistance of modified samples were investigated (103 °C curing, ZnCl2 + 103 °C curing, 120 °C curing, and ZnCl2 + 120 °C curing are denoted as 103, ZC-103, 120, and ZC-120, respectively), with the aim of improving the modification effect. The results showed that ZC-103 had the highest fixation rate, and its weight leaching ratio was higher than that of 120. Fourier-transform infrared spectroscopy showed that ZnCl2 did not affect the functional groups of the modified chemicals. The flexural strength and modulus and the compressive strength perpendicular to the grain were highest for ZC-103. In summary, ZC-103 exhibited the highest fixation rate, indicating that the hardener ZnCl2 bridged and increased the interfacial properties between the chemicals and cell walls and therefore increased the potential for macromolecule polycondensation between the chemicals and cell wall materials. This research paves the way for improving the fixation rate of impregnated wood and provides new insights into practical applications.

Quasi-Static Failure Analysis of Honeycomb Sandwich Beam with Composite Facesheets

2010 ◽  
Vol 160-162 ◽  
pp. 855-859 ◽  
Author(s):  
Li Qing Meng ◽  
Yan Wu ◽  
Shi Zhe Chen ◽  
Xue Feng Shu
Keyword(s):  
Sandwich Beam ◽  
Indentation Test ◽  
Core Material ◽  
Honeycomb Core ◽  
Three Point Bending ◽  
Composite Sandwich ◽  
Sandwich Construction ◽  
Honeycomb Sandwich ◽  
Nomex Honeycomb ◽  
Static Failure

Sandwich construction consists of two thin composite or metal facesheets separated by a core material. Despite extensive researches on the sandwich constructions, their mechanical properties and failure behaviours are still not fully understand. The objective of the paper is to use a experimental and theoretical predicting failure mode for sandwich beam consisting of GFRP facesheets and Nomex honeycomb core. Two kinds of composite sandwich beams are observed in quasi-static three-point bending and indentation test.

scholarly journals High Temperature Mechanical Properties of a Vented Ti-6Al-4V Honeycomb Sandwich Panel

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3008
Author(s):  
Lei Shang ◽  
Ye Wu ◽  
Yuchao Fang ◽  
Yao Li
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Cell Walls ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Honeycomb Core ◽  
Compression Performance ◽  
High Temperature Mechanical Properties ◽  
Honeycomb Sandwich ◽  
The Face

For aerospace applications, honeycomb sandwich panels may have small perforations on the cell walls of the honeycomb core to equilibrate the internal core pressure with external gas pressure, which prevent face-sheet/core debonding due to pressure build-up at high temperature. We propose a new form of perforation on the cell walls of honeycomb sandwich panels to reduce the influence of the perforations on the cell walls on the mechanical properties. In this paper, the high temperature mechanical properties of a new vented Ti-6Al-4V honeycomb sandwich panel were investigated. A vented Ti-6AL-4V honeycomb sandwich panel with 35Ti-35Zr-15Cu-15Ni as the filler alloy was manufactured by high-temperature brazing. The element distribution of the brazed joints was examined by means of SEM (scanning electron microscopy) and EDS (energy-dispersive spectroscopy) analyses. Compared to the interaction between the face-sheets and the brazing filler, the diffusion and reaction between the honeycomb core and the brazing filler were stronger. The flatwise compression and flexural mechanical properties of the vented honeycomb sandwich panels were investigated at 20, 160, 300, and 440 °C, respectively. The flatwise compression strength, elastic modulus, and the flexural strength of the vented honeycomb sandwich panels decreased with the increase of temperature. Moreover, the flexural strength of the L-direction sandwich panels was larger than that of the W-direction sandwich panels at the same temperature. More importantly, the vented honeycomb sandwich panels exhibited good compression performance similar to the unvented honeycomb sandwich panels, and the open holes on the cell walls have no negative effect on the compression performance of the honeycomb sandwich panels in these conditions. The damage morphology observed by SEM revealed that the face-sheets and the brazing zone show ductile and brittle fracture behaviors, respectively.

scholarly journals Pembuatan dan Pengujian Panel Honeycomb Sandwich dengan Inti Berbentuk Gelombang Berbahan Komposit Serat Bambu

2021 ◽  
Vol 5 (2) ◽  
pp. 165-177
Author(s):  
Marsono Marsono ◽  
Sarah Fauziyyah Hanifa ◽  
Faizal Akbar
Keyword(s):  
Flexural Strength ◽  
Fiber Composite ◽  
Turbine Blades ◽  
Bamboo Fiber ◽  
Bending Test ◽  
Honeycomb Core ◽  
Vertical Axis Wind Turbine ◽  
Honeycomb Sandwich ◽  
Core Height ◽  
Strength And Stiffness

ABSTRAKDalam penelitian ini, komposit serat bambu dibuat menjadi panel struktur honeycomb sandwich dan diuji untuk mengukur kemungkinan pemanfaatannya sebagai bahan untuk membuat sudu turbin angin sumbu vertical. Honeycomb sanwich serat bambu yang dibuat memiliki inti (core) yang berbentuk gelombang sinus pada arah memanjang panel. Sebagai pengikat pada komposit ini digunakan resin polyester. Panel honeycomb sandwich yang dibuat memiliki panjang 500mm dan lebar 200mm, sedangkan tebal panel dibuat dengan  dua variasi, yaitu dengan tinggi inti honeycomb 12mm dan  17mm. Panel honeycomb sandwich ini diuji dengan uji bending untuk mendapatkan angka kekuatan lentur (flexural strength) dan angka kekakuan (stiffness). Dari tiga panel yang dibuat identik untuk masih-masing ketinggian inti honeycomb, diperoleh angka kekuatan lentur dan kekakuan terbesar pada panel dengan ketinggian inti honeycomb17mm, yaitu dengan angka kekuatan lentur 0,91kg/mm2 dan angka kekakuan 11,35kg/mmKata kunci: honeycomb sandwich, komposit serat bambu,gelombang sinus,kekuatan lentur, kekakuan.  ABSTRACTIn this research, bamboo fiber composite are made into honeycomb sandwich structure panel and to be tested for its ability as a material for vertical axis wind turbine blades. Bamboo fiber honeycomb sandwich had a sinusoidal-shaped core in the longitudinal direction of the panel. Polyester resin was used as a binder on this composite. The honeycomb panels that have been made have a length of 500mm and a width of 200mm. The thickness of the panels was made of two variations, which was has 12mm and 17mm honeycomb core-height. The honeycomb sandwich panel was tested by bending test to obtain flexural strength and stiffness. From the three panels that have been made in identical dimension for each honeycomb core-height, the highest flexural strength and stiffness was obtained in the specimen with the honeycomb core-height of 17mm, with a flexural strength of 0,91kg/mm2 and astiffness of 11,35kg/mm. Keywords: honeycomb sandwich, bamboo fiber composite, sinusoidal wave,  flexurall strength, stiffness.

Out-of-plane shear property analysis of Nomex honeycomb sandwich structure

2020 ◽  
pp. 073168442094328 ◽  
Author(s):  
Yue Liu ◽  
Wei Liu ◽  
Weicheng Gao
Keyword(s):  
Shear Strength ◽  
Shear Modulus ◽  
Sandwich Structure ◽  
Honeycomb Core ◽  
Plane Shear ◽  
Honeycomb Sandwich ◽  
Out Of Plane ◽  
Nomex Honeycomb ◽  
Analytical Expressions ◽  
Honeycomb Sandwich Structure

Honeycomb sandwich structure finds immense applications in aerospace manufacturing and other similar fields. The Nomex honeycomb sandwich structural material exhibits a complex structure and boundary conditions, making it difficult to obtain exact solutions for the equivalent out-of-plane shear modulus and shear strength of the Nomex honeycomb using current analytical methods. To this end, based on the energy method, the Kelsey model is simplified in this paper. Then, distribution of the shear forces in the longitudinal and transverse directions of the Nomex honeycomb core is analysed using the simplified model. Considering the effect of the wall thickness of the honeycomb core on the ultimate strength, the analytical expressions of the out-of-plane shear modulus and shear strength of the Nomex honeycomb are proposed. The shear properties and failure process of the Nomex honeycomb in two directions are then analysed experimentally. The accuracy of the analytical expressions of the equivalent shear modulus and shear strength is verified experimentally. The equivalent out-of-plane shear modulus and shear strength of the honeycomb was demonstrated to be effectively predicted by the analytical approach.

Influence of mosaic pattern on hygrothermally-aged filament wound composite cylinders under axial compression

2020 ◽  
Vol 54 (19) ◽  
pp. 2651-2659 ◽  
Author(s):  
Cristiano B Azevedo ◽  
José Humberto S Almeida Jr ◽  
Heitor F Flores ◽  
Frederico Eggers ◽  
Sandro C Amico
Keyword(s):  
Compressive Strength ◽  
Composite Structures ◽  
Mechanical Response ◽  
Filament Winding ◽  
Environmental Conditioning ◽  
Filament Wound ◽  
Filament Wound Composite ◽  
Strength And Stiffness ◽  
Hygrothermal Conditioning ◽  
Wound Composite

The mechanical response of composite structures may be affected by harsh environments, particularly when the matrix has a major contribution, e.g. with off-axis plies. This study aims at investigating the influence of the winding pattern on the axial compressive behavior of filament wound composite cylinder under hygrothermal conditioning. Carbon fiber-reinforced epoxy cylinders were manufactured via filament winding with 1/1, 3/1, and 5/1 mosaic winding patterns and submitted to distilled and artificial seawater environmental conditioning. Water uptake for each hygrothermal conditioning was periodically monitored. The winding pattern influenced both compressive strength and stiffness, and the environmental conditioning decreased strength up to ≈10%. The winding pattern with three diamonds around the circumference of the cylinders provides the properties in term of compressive strength and stiffness.

Improvement in skin–core adhesion of multiwalled carbon nanotubes modified carbon fiber prepreg/Nomex honeycomb sandwich composites

2017 ◽  
Vol 36 (8) ◽  
pp. 608-618 ◽  
Author(s):  
Chao Chen ◽  
Yanxia Li ◽  
Yizhuo Gu ◽  
Min Li ◽  
Zuoguang Zhang
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Fiber ◽  
Multiwalled Carbon Nanotubes ◽  
Peel Test ◽  
Sandwich Composites ◽  
Honeycomb Core ◽  
Multiwalled Carbon ◽  
Honeycomb Sandwich ◽  
The Matrix ◽  
Nomex Honeycomb

An experimental investigation on the sandwich composites composed of the carbon fiber face sheets and Nomex honeycomb core has been carried out in this study. Multiwalled carbon nanotubes were added into the matrix of prepreg for converting the traditional pure resin adhesive fillet to composites. Resin viscosity was measured to evaluate the effect of the additive amount of multiwalled carbon nanotubes on the rheological properties. The size of adhesive fillet was obtained from the optical microscopy to assess the forming quality. Climbing drum peel test and edgewise compression test were employed for the mechanical assessment. The results showed that the addition of multiwalled carbon nanotubes reinforcement to epoxy resin in the prepreg was very effective in improving the skin–core adhesion. The peel load and peel energy release rate as well as the edgewise compressive strength and edgewise compressive modulus of the sandwich composites varied with different magnitudes due to the additive amount of multiwalled carbon nanotubes. Reinforcing mechanism of the adhesive fillet with multiwalled carbon nanotubes reinforcement was discussed on the basis of the fractographic observations by scanning electron microscopy.

Behavior of Indented Sandwiches Structure with Nomex Honeycomb Core and Metallic Skins Subjected to Compressive Loading (CAI)

2007 ◽  
Vol 345-346 ◽  
pp. 729-732
Author(s):  
Y. Aminanda ◽  
B. Castanie ◽  
J.J. Barrau
Keyword(s):  
Residual Strength ◽  
Compressive Loading ◽  
Element Model ◽  
Honeycomb Core ◽  
Uniform Compression ◽  
Compression Load ◽  
Damage Area ◽  
Result Show ◽  
Nomex Honeycomb ◽  
Test Result

A finite element model is proposed to determine the residual strength and the evolution of damage area of indented sandwiches structures with Nomex honeycomb core and metallic skins indented by a spherical indenter under longitudinal compression load (CAI). The honeycomb is represented by a grid of non-linear springs which its behavior law is obtained by performing simple transverse uniform compression test on a block of honeycomb alone.The comparisons between computation and test result show that the model can simulate accurately the form of damage geometry during indentation, its residual print when the load is relieved (relaxation) and the residual strength and the evolution of damage geometry during CAI.

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